How to save environment variable on my Ubuntu Linux system

I am using Maven to the build process of my Java project.

To launch the mvn command in any position within the shell I am using the following command to declare the environment variable in this way:

export MAVEN_HOME=/home/andrea/SpringSource/apache-maven-3.0.4

export PATH=$PATH:$MAVEN_HOME/bin

The problem is that if I close my shell, when I open it again I have to give again the previous commands...how can I solve this problem and "save" the environment variable on my system?

Thank you

Andrea